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Etching grounds
All these grounds may be thinned using quick drying petroleum, essence of turpentine and F-essence, except mastic grounds which must only be thinned using quick drying petroleum. They are applied with a soft and very wide brush or with a roller. Before applying these grounds, it is imperative that all grease be removed from the plate. To do this, thin some Marly white with a small quantity of water and rub the plate with a soft cloth or a piece of cotton. Rinse under flowing water: Pour a soured solution of vinegar and salt on the plate. Rinse once again. Dry rapidly. Avoid putting fingers on the plate whilst carrying out these operations. CHARBONNEL HARD BLACK BALL GROUND (solid) Once the ground is applied and dry, the picture is etched with a hard point in order to expose the metal beneath the ground. The plate is then placed in a bath of acid to erode the exposed metal. Once the required bite depth has been attained, the plate should be taken out of the acid bath solution and dried and the ground removed with the appropriate thinner:
ULTRAFLEX LIQUID GROUND
LAMOUR BLACK SATIN VARNISH
Soft grounds protect the plate. They are non-drying grounds, applied with a painting dabber or roller: Textures and materials pressed into their non-drying surface will lift off, leaving the metal bared, ready for the bite of the acid. The plate must be heated before application. The "Pencil Method" consists of drawing with a hard point on "laid" paper applied over the soft ground. The paper sticks to the drawn parts. After the bite of the acid, a pencil stroke effect is obtained. CHARBONNEL SOFT BLACK BALL GROUND (solid)
After leaving the plate in acid for the required time, remove the plate from the acid bath solution and remove the ground using the appropriate thinner: The amount of time you leave the plate in the acid depends on the acid's strength (measured using an acetometer), the room temperature and the depth you wish to give the stroke. The etching is then ready and on!y the finishing touches need be applied. A retouching ground can be applied to the plate which may then be retouched as required following the lines of the previous etching. CHARBONNEL HARD WHITE BALL GROUND (solid)
TRANPARENT LIQUID VARNISH
These are used to rework a plate that has been etched deep enough by the acid. They protect the surface of the plate without flowing into the recesses. They are, therefore, used to give the etched lines greater depth due to a fresh exposure to acid. LAMOUR SOFT BLACK GROUND
REBITING ROLLER GROUND
These are applied cold with a paintbrush. Applied to the back and the edges of the plate, they serve to protect these parts from the bite of the acid. They are extremely resistant. LAMOUR BLACK COVERING VARNISH
ALCOHOL VARNISH
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